Manipulating cannabinoid receptors in female mice significantly altered ovarian follicle development, estrogen levels, and blood vessel formation, with CB2 receptors playing a particularly important role.
Reproductive health researchers, women using cannabis who are considering pregnancy, fertility specialists
CB2 receptor blocking increased follicle development and estrogen levels in mice
What the researchers found
CB2 receptor blocking increased primary, preantral, and antral follicles along with ovarian volume, weight, and estrogen levels. CB1 blocking increased ovarian blood vessel density. Combined agonist+antagonist treatment altered key endocannabinoid-processing enzyme expression (decreased NAPE-PLD, increased FAAH).
Why it matters
Understanding how the endocannabinoid system regulates ovarian function is critical as cannabis use rises among women of reproductive age. These findings suggest cannabis could meaningfully affect fertility.
The numbers in context
80 mice in 10 groups. CB2 antagonist (AM630) increased follicle numbers across developmental stages. CB1 antagonist (AM251) increased microvascular density. 5-day treatment protocol.
How the study worked
Controlled animal study using 80 female NMRI mice divided into 10 groups, receiving CB1/CB2 agonists, antagonists, or combinations for 5 days, followed by ovarian analysis including histology, gene expression, and hormone measurement.
What this study cannot tell us
Mouse reproductive physiology differs from human. Short 5-day treatment may not reflect chronic cannabis use. Pharmacological agonists/antagonists are not identical to cannabis. Small sample per group.
How to read the evidence
Well-controlled animal study with multiple outcome measures, but mouse reproductive physiology has important differences from human.
When this study was published
2025 animal study with novel findings on cannabinoid-ovarian interactions.
The bigger picture
The endocannabinoid system appears deeply embedded in reproductive physiology. As cannabis use among women of reproductive age increases, understanding these mechanisms becomes more than academic.
Questions still open
- Does regular cannabis use affect fertility in women through these mechanisms? Could cannabinoid receptor modulation be therapeutic for certain fertility conditions? Are these effects reversible?
Common questions
Does cannabis affect fertility?
Which cannabinoid receptor matters more for ovarian function?
Read the original research
The role of cannabinoid agonists and antagonists on folliculogenesis and evolutionary events in the mouse ovary.
Iranian journal of basic medical sciences, 28(9), 1171-1179
Citation
Mirzaie, Vida; Eslaminejad, Touba; Sheikhbahaei, Fatemeh; Vafaei, Shayan; Nabipour, Fatemeh; Behzadi, Mina; Nematollahi-Mahani, Seyed Noureddin. (2025). The role of cannabinoid agonists and antagonists on folliculogenesis and evolutionary events in the mouse ovary.. Iranian journal of basic medical sciences, 28(9), 1171-1179. https://doi.org/10.22038/ijbms.2025.85417.18468
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